This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 10 |
| 3 | 84 |
| 4 | 2380 |
| 5 | 237336 |
| 6 | 82598880 |
| 7 | 99949406400 |
| 8 | 422825581068000 |
| 9 | 6318976181520699840 |
| 10 | 337559127276933693852160 |
| 11 | 65182103393445184131620004864 |
| 12 | 45946437874792132748338425828443136 |